Megacities to impact world climate

The expansion of the world's "megacities" will have significant climate impacts, computer modeling by U.S. researchers suggests. Hoping to quantify the impact of rapidly expanding megapolitan areas on regional climate, researchers from Arizona State University and the National Center for Atmospheric Research in Colorado have established local maximum summertime warming resulting from projected expansion of Arizona's urban Sun Corridor could approach 7 degrees Fahrenheit. The Sun Corridor is the most rapidly growing megapolitan area in the United States, composed of four metropolitan areas: Phoenix, Tucson, Prescott and Nogales. With a population projection expected to exceed 9 million people by 2040, it provides a unique opportunity to diagnose the influence of large-scale urbanization on climate and its relation to global climate change, an ASU release said Sunday. "We posed a fundamental set of questions in our study, examining the different scenarios of Sun Corridor expansion through mid-century," Matei Georgescu, lead author and professor in the ASU school of geographical sciences and urban planning, said. "The worst case expansion scenario we utilized led to local maximum summer warming of nearly 4 degrees Celsius (7 degrees F.) In the best case scenario, where Sun Corridor expansion is both more constrained and urban land use density is lower, our results still indicate considerable local warming, up to about 2 degrees Celsius (3.5 degrees F,)" Georgescu said.